U.S. patent application number 12/594860 was filed with the patent office on 2010-05-13 for thermoplastic resin composition for blow molding and blow molded articles thereof.
This patent application is currently assigned to TECHNO POLYMER CO., LTD.. Invention is credited to Masahiko Nagasaka, Junichiro Nitta, Kazuhiro Okamoto.
Application Number | 20100119750 12/594860 |
Document ID | / |
Family ID | 40074753 |
Filed Date | 2010-05-13 |
United States Patent
Application |
20100119750 |
Kind Code |
A1 |
Okamoto; Kazuhiro ; et
al. |
May 13, 2010 |
THERMOPLASTIC RESIN COMPOSITION FOR BLOW MOLDING AND BLOW MOLDED
ARTICLES THEREOF
Abstract
A thermoplastic resin composition for blow molding is disclosed,
which comprises a styrene based resin composition (A) containing a
graft copolymer (A-1) containing an .alpha.,.beta.-unsaturated
glycidyl ester compound, a graft copolymer (A-2) not containing an
.alpha.,.beta.-unsaturated glycidyl ester compound and a copolymer
(A-3), and an antistatic agent (B). According to the thermoplastic
resin composition for blow molding of the present invention, blow
molded articles are provided, which are excellent not only in
surface property, impact resistance and heat resistance, but also
in effects of suppressing adhesion of polished powder generated in
a sanding process and dust during storage until the coating
process, and further, the thermoplastic resin composition for blow
molding which is reduced in adhesion property to a metal and is
excellent in resistance to drawdown, and blow molded articles
therefrom are provided.
Inventors: |
Okamoto; Kazuhiro; (Tokyo,
JP) ; Nitta; Junichiro; (Tokyo, JP) ;
Nagasaka; Masahiko; (Tokyo, JP) |
Correspondence
Address: |
KRATZ, QUINTOS & HANSON, LLP
1420 K Street, N.W., Suite 400
WASHINGTON
DC
20005
US
|
Assignee: |
TECHNO POLYMER CO., LTD.
Tokyo
JP
|
Family ID: |
40074753 |
Appl. No.: |
12/594860 |
Filed: |
May 23, 2008 |
PCT Filed: |
May 23, 2008 |
PCT NO: |
PCT/JP2008/001292 |
371 Date: |
October 6, 2009 |
Current U.S.
Class: |
428/36.8 ;
524/504 |
Current CPC
Class: |
C08K 5/0075 20130101;
B29C 49/0005 20130101; C08F 279/02 20130101; Y10T 428/1386
20150115; B29C 51/002 20130101; B29C 2049/4605 20130101; B29C
2049/4608 20130101; C08L 51/003 20130101; C08K 5/0075 20130101;
B29C 51/10 20130101; C08L 51/04 20130101; B29C 2049/4626 20130101;
B29C 49/04 20130101; C08F 265/04 20130101 |
Class at
Publication: |
428/36.8 ;
524/504 |
International
Class: |
B29D 22/00 20060101
B29D022/00; C08L 51/04 20060101 C08L051/04 |
Foreign Application Data
Date |
Code |
Application Number |
May 30, 2007 |
JP |
2007-143081 |
Claims
1. A thermoplastic resin composition for blow molding comprises;
100 parts by weight of a styrene based resin composition (A)
containing 0.1 to 30% by weight of the following graft copolymer
(A-1), 1 to 54.9% by weight of the following graft copolymer (A-2),
and 45 to 95% by weight of the following copolymer (A-3), the total
of the graft copolymer (A-1), the graft copolymer (A-2), and the
copolymer (A-3) being 100% by weight, and 0.1 to 10 parts by weight
of an antistatic agent (B) with a melting point of 170.degree. C.
or lower: (A-1): a graft copolymer obtained by polymerizing 95 to 5
parts by weight of a monomer mixture containing 0.1 to 30.2% by
weight of an .alpha.,.beta.-unsaturated glycidyl ester compound,
9.9 to 40% by weight of a vinyl cyanide compound, and 59.9 to 90%
by weight of an aromatic vinyl compound, the total of the monomers
being 100% by weight, in the presence of 5 to 95 parts by weight of
a rubber type polymer, wherein the total of the rubber type polymer
and the monomer mixture is 100 parts by weight; (A-2): a graft
copolymer obtained by polymerizing 95 to 5 parts by weight of a
monomer mixture containing 10 to 40% by weight of a vinyl cyanide
compound and 60 to 90% by weight of an aromatic vinyl compound, the
total of the monomers being 100% by weight, in the presence of 5 to
95 parts by weight of a rubber type polymer, wherein the total of
the rubber type polymer and the monomer mixture is 100 parts by
weight, and (A-3): a copolymer obtained by polymerizing a monomer
mixture containing 5 to 40% by weight of a vinyl cyanide compound,
45 to 95% by weight of an aromatic vinyl compound, and 0 to 50% by
weight of other vinyl compounds copolymerizable with these
monomers, the total of the monomers being 100% by weight.
2. The thermoplastic resin composition for blow molding of claim 1,
wherein a melting point of the antistatic agent (B) is 40 to
170.degree. C.
3. The thermoplastic resin composition for blow molding of claim 2,
wherein 0.01 to 10 parts by weight of at least one compound (C)
selected from the group consisting of hydroxides and carbonates of
alkali metals, hydroxides, carbonates, and oxides of alkaline earth
metals, 0.01 to 5 parts by weight of talc (D), and 0.01 to 5 parts
by weight of a polyolefin based wax (E) are further blended with
100 parts by weight of the styrene based resin composition (A).
4. A blow molded article obtained by blow molding the thermoplastic
resin composition for blow molding as described in claim 3.
5. The thermoplastic resin composition for blow molding of claim 1,
wherein 0.01 to 10 parts by weight of at least one compound (C)
selected from the group consisting of hydroxides and carbonates of
alkali metals, hydroxides, carbonates, and oxides of alkaline earth
metals, 0.01 to 5 parts by weight of talc (D), and 0.01 to 5 parts
by weight of a polyolefin based wax (E) are further blended with
100 parts by weight of the styrene based resin composition (A).
6. A blow molded article obtained by blow molding the thermoplastic
resin composition for blow molding as described in claim 5.
7. A blow molded article obtained by blow molding the thermoplastic
resin composition for blow molding as described in claim 1.
8. A blow molded article obtained by blow molding the thermoplastic
resin composition for blow molding as described in claim 2.
Description
TECHNICAL FIELD
[0001] The present invention relates to a thermoplastic resin
composition for blow molding excellent in surface property of a
molded article thereof, impact resistance, and heat resistance as
well as blow moldability such as resistance to drawdown, and a blow
molded article obtained by molding the composition. Further, the
present invention relates to a thermoplastic resin composition for
blow molding which gives a molded article having a surface to which
a polished powder of the molded article generated in a sanding
process before coating scarcely adheres and also gives a molded
article having a surface to which dust scarcely adheres during
storage until the coating process and therefore which makes it easy
to carry out a work for removing them before coating, and a blow
molded article obtained by molding the composition. Furthermore,
the present invention relates to a thermoplastic resin composition
for blow molding with low adhesion of the resin to a metal.
BACKGROUND ART
[0002] Conventionally, thermoplastic resins such as high density
polyethylene, low density polyethylene, linear low density
polyethylene and polyvinyl chloride have been employed as a
material for blow molding in order to produce bottles or the like.
Recently, so-called engineering plastics excellent in thermal
properties and mechanical properties have been employed for
electric and electronic appliances such as an air duct and lighting
equipments, automotive parts such as an air spoiler and a console,
furniture parts such as a top panel of a desk, and the like (e.g.
Patent Document 1).
[0003] The above-mentioned blow molded articles of the engineering
plastics and the like have a large number of small recessed parts
(hereinafter, referred to as recesses) on the surfaces formed
during the blow molding and, for example, an air spoiler for which
a smooth coating surface is required, secondary processability by
sanding has often been needed before coating. In this connection,
it is supposed that the above-mentioned recesses are generated in a
manner that a gas which is not completely extracted from the
parting face of a mold and left between a parison made of a melted
engineering plastic and the mold surface during the blow molding is
left in form of a large number of small spheres on the molded
article surface and thereafter, the engineering plastic is cooled
and solidified.
[0004] On the other hand, ABS resin compositions for blow molding
having resistance to formation of recesses on the surface of a blow
molded article and excellent in impact resistance, heat resistance,
rigidity, and blow moldability by blending specified amounts of
specified graft copolymers and copolymers have been proposed (e.g.
Patent Document 2).
[0005] However, even if products such as an air spoiler for which a
smooth coating surface is required are produced using any of the
above-mentioned materials for blow molding, polished powder of the
molded article generated in a sanding process before coating
adheres to the molded article surfaces or, for example, airborne
dust adheres to the product surfaces during storage until the
coating process, so that a work for removing them has to be carried
out before the coating and the productivity may be lowered in some
cases.
[0006] Further, the above-mentioned materials for blow molding all
have high adhesion of the resin to a metal and therefore, at the
time of forming a parison by extruding melted resin out of a die at
the time of blow molding, the melted resin adheres to the metal
surface of the die or the like to make smooth molding impossible or
the adhered resin causes decomposition or thermal deterioration and
becomes foreign matters to thereby blemish the surface appearance
of the blow molded articles in some cases.
[0007] Furthermore, since a resin tends to adhere to the metal
surface such as a screw surface, a barrel inner wall, or the like
of a blow molding apparatus, an extruder, or the like, it sometimes
becomes impossible to efficiently carry out purging of the resin or
the replacement work for the resin.
[0008] Patent Document 1: Japanese Patent Application Laid-Open
(JP-A) No. 7-32454
[0009] Patent Document 2: JP-A No. 2001-214026
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0010] The inventors of the present invention have made various
investigations to solve the above-mentioned problems and have found
that addition of a specified amount of a specified antistatic agent
to a resin composition containing specified components and also
addition of a specified antistatic agent and specified substances
give the resin composition good surface property of a blow molded
article of the composition, impact resistance, heat resistance, and
blow moldability such as resistance to drawdown or the like.
Further, the inventors of the present invention have also found
that since a polished powder of a molded article generated in the
sanding process before coating hardly adheres to the molded article
surface and dust hardly adheres to the molded article surface
during storage until the coating process, the work for removing
them before coating can be lessened. Moreover, the inventors of the
present invention have found that since the adhesion of the resin
to a metal is also low, even if the melted resin is extruded out of
a die at the time of blow molding, the melted resin hardly adheres
to the metal surface of the die or the like and thus molding is
carried out smoothly. Furthermore, the inventors of the present
invention have also found that since the resin hardly adheres to
the metal surfaces such as screw surface, barrel inner wall, or the
like of a blow molding apparatus and the resin is easily peeled off
from the above-mentioned metal surfaces, the workability of
replacing the resin becomes excellent. These findings have now led
to the completion of the thermoplastic resin composition for blow
molding of the present invention and a blow molded article obtained
by molding the composition.
Means for Solving the Problems
[0011] To attain the above-mentioned objects, the present invention
possesses the following characteristics 1 to 4.
[0012] 1. A thermoplastic resin composition for blow molding
comprises 100 parts by weight of a styrene based resin composition
(A) containing 0.1 to 30% by weight of the following graft
copolymer (A-1), 1 to 54.9% by weight of the following graft
copolymer (A-2), and 45 to 95% by weight of the following copolymer
(A-3) (the total of the graft copolymer (A-1), the graft copolymer
(A-2), and the copolymer (A-3) being 100% by weight) and 0.1 to 10
parts by weight of an antistatic agent (B) with a melting point of
170.degree. C. or lower:
[0013] (A-1): a graft copolymer obtained by polymerizing 95 to 5
parts by weight of a monomer mixture containing 0.1 to 30.2% by
weight of an .alpha.,.beta.-unsaturated glycidyl ester compound,
9.9 to 40% by weight of a vinyl cyanide compound, and 59.9 to 90%
by weight of an aromatic vinyl compound (the total of the monomers
being 100% by weight), in the presence of 5 to 95 parts by weight
of a rubber type polymer (the total of the rubber type polymer and
the monomer mixture being 100 parts by weight),
[0014] (A-2): a graft copolymer obtained by polymerizing 95 to 5
parts by weight of a monomer mixture containing 10 to 40% by weight
of a vinyl cyanide compound and 60 to 90% by weight of an aromatic
vinyl compound (the total of the monomers being 100% by weight), in
the presence of 5 to 95 parts by weight of a rubber type polymer
(the total of the rubber type polymer and the monomer mixture being
100 parts by weight), and
[0015] (A-3): a copolymer obtained by polymerizing a monomer
mixture containing 5 to 40% by weight of a vinyl cyanide compound,
45 to 95% by weight of an aromatic vinyl compound, and 0 to 50% by
weight of other vinyl compounds copolymerizable with these monomers
(the total of the monomers being 100% by weight).
[0016] 2. The thermoplastic resin composition for blow molding as
described in the above-mentioned invention 1, wherein the melting
point of the antistatic agent (B) is 40 to 170.degree. C.
[0017] 3. The thermoplastic resin composition for blow molding as
described in the above-mentioned invention 1 or 2, wherein 0.01 to
10 parts by weight of at least one compound (C) selected from the
group consisting of hydroxides and carbonates of alkali metals,
hydroxides, carbonates, and oxides of alkaline earth metals, 0.01
to 5 parts by weight of talc (D), and 0.01 to 5 parts by weight of
a polyolefin based wax (E) are further blended with 100 parts by
weight of the styrene based resin composition (A).
[0018] 4. A blow molded article obtained by blow molding the
thermoplastic resin composition for blow molding as described in
any one of the above-mentioned inventions 1 to 3.
EFFECTS OF THE INVENTION
[0019] The thermoplastic resin composition for blow molding of the
present invention is excellent in surface property of a blow molded
article, impact resistance, heat resistance, and blow moldability
such as resistance to drawdown. Further, by blending the specified
antistatic agent in the specified amounts, polished powder
generated in a sanding process before coating is difficult to
adhere to the surface of the molded article, and dust is also
difficult to adhere to the surface of the molded article during
storage until the coating process. Accordingly, the work for
removing them before coating is lessened and productivity of the
blow molded article can be remarkably improved.
[0020] Further, blending at least one compound (C) selected from
the group consisting of hydroxides and carbonates of alkali metals,
hydroxides, carbonates, and oxides of alkaline earth metals, talc
(D), and a polyolefin based wax (E) to the above-mentioned
thermoplastic resin composition for blow molding lowers the
adhesion of the resin composition to a metal. Accordingly, since
the resin composition hardly adheres to the metal surface of a die
or the like at the time of blow molding, the above-mentioned resin
composition hardly causes thermal deterioration and decomposition,
and therefore, there is less possibility of damaging surface
appearance of the blow molded article. Further, since the resin
composition hardly adheres to the metal surfaces of the screw
surface and the barrel inner wall of a blow molding apparatus, the
workability of purging and replacing the resin becomes excellent
and the productivity can remarkably be improved.
[0021] Moreover, fine irregularities are formed on the parison
surface at the time of blow molding, gas purging between the
parison surface and the mold surface occurs well. Furthermore,
since formation of recesses larger than the fine irregularities can
be suppressed, the work needed for the secondary processability
such as sanding to obtain a smooth coating surface can be lessened.
Consequently, the present invention is remarkably useful as a
thermoplastic resin composition for blow molding for obtaining a
blow molded article such as an air spoiler or the like which is
required to have beautiful surface appearance and as a blow molded
article obtained by molding the composition.
BRIEF DESCRIPTION OF DRAWINGS
[0022] FIG. 1(a) is a front view showing the setting method of a
cylindrical blow molded article in a low temperature falling weight
test and FIG. 1(b) is a side view of the same.
EXPLANATION OF THE SYMBOLS
[0023] 1. A cylindrical blow molded article 2. A parting line 3. A
tool for fixing a molded article
BEST MODE FOR CARRYING OUT THE INVENTION
[0024] Hereinafter, the present invention will be described in more
detail. In this specification, "(co)polymerization" means
homopolymerization and copolymerization, "(meth)acryl" means acryl
and/or methacryl, and "(meth)acrylate" means acrylate and/or
methacrylate.
[0025] The thermoplastic resin composition for blow molding of the
present invention is obtained by blending the specified amount of
an antistatic agent (B) with a styrene based resin composition (A)
containing the specified graft copolymers (A-1) and (A-2), and a
copolymer (A-3) in the specified amounts. Further, if necessary,
the specified amounts of an alkali metal compound or the like (C),
talc (D), and a polyolefin based wax (E) are blended.
Styrene Based Resin Composition (A)
[0026] The styrene based resin composition comprises the following
graft copolymers (A-1) and (A-2), and a copolymer (A-3).
A Graft Copolymer (A-1): (Hereinafter, Also Referred to as
"Component (A-1)")
[0027] The component (A-1) to be used in the present invention is a
graft copolymer obtained by polymerizing, in the presence of 5 to
95 parts (parts by weight, unless otherwise specified, the same
applies hereinafter), preferably 10 to 90 parts of a rubber type
polymer, 5 to 95 parts, preferably 10 to 90 parts of a monomer
mixture containing 0.1 to 30.2% (% by weight, unless otherwise
specified, the same applies hereinafter), preferably 0.1 to 25% of
an .alpha.,.beta.-unsaturated glycidyl ester compound, 9.9 to 40%,
preferably 9.9 to 35% of a vinyl cyanide compound, and 59.9 to 90%,
preferably 64.9 to 90% of an aromatic vinyl compound (the total of
the monomers being 100%) in such a manner that the total of the
rubber type polymer and the monomer mixture is adjusted to be 100
parts.
[0028] In the above-mentioned component (A-1), if the amount of the
rubber type polymer is less than 5 parts, the impact resistance is
lowered and on the other hand, if it exceeds 95 parts, the heat
resistance, blow moldability, and secondary processability such as
sanding are lowered. Further, if the amount of the
.alpha.,.beta.-unsaturated glycidyl ester compound is less than
0.1%, the effect of suppressing formation of recesses and making
the surface uniform becomes insufficient and on the other hand, if
it exceeds 30.2%, the impact resistance is lowered. Further, if the
amount of the vinyl cyanide compound is less than 9.9%, the impact
resistance is lowered and on the other hand, if it exceeds 40%, the
heat resistance is lowered. Furthermore, if the amount of the
aromatic vinyl compound is less than 59.9%, the moldability becomes
insufficient and on the other hand, if it exceeds 90%, the impact
resistance is lowered.
[0029] Examples of the rubber type polymer to be used for the
above-mentioned component (A-1) include conjugated diene based
rubbers such as polybutadienes, butadiene-styrene copolymers (SBR),
butadiene-acrylonitrile copolymers (NBR), butadiene-acrylic acid
ester copolymers, or the like; ethylene-.alpha.-olefin based
rubbers such as ethylene-propylene copolymers (EPR),
ethylene-propylene non-conjugated diene copolymers (EPDM), or the
like; acrylic rubbers such as polybutyl acrylate, poly-2-ethylhexyl
acrylate, or the like; silicone rubbers; and silicone-acryl
compounded rubbers. They may be used alone or two or more of them
may be used in form of a mixture. Among them, polybutadiene is
preferable from the viewpoint of improvement of the impact
resistance of the blow molded articles. The weight average particle
diameter of the rubber type polymer is preferably 0.05 to 2 .mu.m,
more preferably 0.05 to 1.5 .mu.m, and even more preferably 0.15 to
1.2 .mu.m from the viewpoint of improvement of impact
resistance.
[0030] Examples of the .alpha.,.beta.-unsaturated glycidyl ester
compound include glycidyl acrylate, glycidyl methacrylate, glycidyl
ethacrylate, or the like. They may be used alone or two or more of
them may be used in form of a mixture.
[0031] Examples of the above-mentioned vinyl cyanide compound
include acrylonitrile, methacrylonitrile, or the like and they may
be used alone or two or more of them may be used in form of a
mixture. Among them, preferable is acrylonitrile.
[0032] Examples of the above-mentioned aromatic vinyl compound
include styrene, .alpha.-methylstyrene, methylstyrene, vinylxylene,
monochlorostyrene, dichlorostyrene, monobromostyrene,
dibromostyrene, fluorostyrene, p-tert-butylstyrene, ethylstyrene,
vinylnaphthalene, or the like and they may be used alone or two or
more of them may be used in form of a mixture. Among them,
preferable are styrene and .alpha.-methylstyrene.
[0033] The above-mentioned monomer mixture may contain, if
necessary, other copolymerizable vinyl based compounds. Examples of
the copolymerizable vinyl based compounds include acrylic acid
alkyl esters such as methyl acrylate, ethyl acrylate, propyl
acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl
acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl
acrylate, or the like; methacrylic acid alkyl esters such as methyl
methacrylate, ethyl methacrylate, propyl methacrylate, butyl
methacrylate, amyl methacrylate, hexyl methacrylate, octyl
methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate,
dodecyl methacrylate, octadecyl methacrylate, phenyl methacrylate,
benzyl methacrylate, or the like; unsaturated acid anhydrides such
as maleic anhydride, itaconic anhydride, or the like; unsaturated
acids such as acrylic acid, methacrylic acid, or the like; and
.alpha.,.beta.-unsaturated dicarboxylic acid imide compounds such
as maleimide, N-methylmaleimide, N-butylmaleimide,
N-phenylmaleimide, N-cyclohexylmaleimide, or the like and they may
be used alone or two or more of them may be used in form of a
mixture. Among them, preferable are methyl methacrylate,
N-phenylmaleimide, and N-cyclohexylmaleimide. The amount to be used
of the above-mentioned other copolymerizable monomers is preferably
0 to 30% and more preferably 0 to 25% when the amount of the entire
monomer mixture is 100%. If the amount to be used of the other
copolymerizable monomers exceeds 30%, the balance among the surface
property of a blow molded article, impact resistance, heat
resistance, blow moldability, suppressing adhesion of polished
powder and dust, and resistance to adhesion to a metal tends to be
lowered.
[0034] The Graft Copolymer (A-2): (Hereinafter, Also Referred to as
"Component (A-2)")
[0035] The component (A-2) to be used in the present invention is a
graft copolymer obtained by polymerizing, in the presence of 5 to
95 parts, preferably 10 to 90 parts of a rubber type polymer, 95 to
5 parts, preferably 90 to 10 parts of a monomer mixture containing
10 to 40%, preferably 10 to 35% of a vinyl cyanide compound and 60
to 90%, preferably 65 to 90% of an aromatic vinyl compound (the
total of the monomers being 100% by weight) in such a manner that
the total of the rubber type polymer and the monomer mixture is
adjusted to be 100 parts. However, .alpha.,.beta.-unsaturated
glycidyl ester compound is not included as a monomer.
[0036] In the above-mentioned component (A-2), if the amount of the
rubber type polymer is less than 5 parts, the impact resistance is
lowered and on the other hand, if it exceeds 95 parts, the heat
resistance, blow moldability, and secondary processability such as
sanding are lowered. Further, if the amount of the vinyl cyanide
compound is less than 10%, the chemical resistance is lowered and
on the other hand, if it exceeds 40%, the heat resistance is
lowered. Furthermore, if the amount of the aromatic vinyl compound
is less than 60%, the moldability becomes insufficient and on the
other hand, if it exceeds 90%, the impact resistance is
lowered.
[0037] The rubber type polymer to be used in producing the
above-mentioned component (A-2) is the same as the rubber type
polymer used in producing the above-mentioned component (A-1).
[0038] The vinyl cyanide compound to be used in producing the
above-mentioned component (A-2) is the same as the vinyl cyanide
compound used in producing the above-mentioned component (A-1).
[0039] The aromatic vinyl compound to be used in producing the
above-mentioned component (A-2) is the same as the aromatic vinyl
compound used in producing the above-mentioned component (A-1).
[0040] The monomers to be used in production of the above-mentioned
component (A-2) may contain, if necessary, other copolymerizable
vinyl based compounds. Examples of the other copolymerizable vinyl
based compounds are the same as those of the other copolymerizable
vinyl based compounds used in production of the component (A-1),
however, .alpha.,.beta.-unsaturated glycidyl ester compound is
excluded. The amount to be used of the above-mentioned other
copolymerizable monomers is preferably 0 to 30% and more preferably
0 to 25% in the case the amount of the entire monomer mixture is
100%. If the amount to be used of the other copolymerizable
monomers exceeds 30%, the balance among the surface property of a
blow molded article, impact resistance, heat resistance, blow
moldability, suppressing adhesion of polished powder and dust, and
resistance to adhesion to a metal tends to be lowered.
[0041] The Copolymer (A-3): (Hereinafter, Also Referred to as
"Component (A-3)")
[0042] The component (A-3) to be used in the present invention is a
copolymer obtained by polymerizing a monomer mixture containing 5
to 40%, preferably 10 to 40%, and more preferably 10 to 35% of a
vinyl cyanide compound, 45 to 95%, preferably 60 to 90%, and more
preferably 65 to 90% of an aromatic vinyl compound, and 0 to 50%,
preferably 0 to 30%, and more preferably 0 to 25% of other vinyl
based compounds copolymerizable with these monomers (the total of
the monomers being 100% by weight). If the amount of the vinyl
cyanide compound is less than 5%, the chemical resistance is
lowered, and on the other hand, if it exceeds 40%, the heat
resistance is lowered. Furthermore, if the amount of the aromatic
vinyl compound is less than 45%, the moldability becomes
insufficient and on the other hand, if it exceeds 95%, the impact
resistance is lowered. If the amount of the other copolymerizable
vinyl based compounds exceeds 50%, the balance among the surface
property of a blow molded article, impact resistance, heat
resistance, blow moldability, suppressing adhesion of polished
powder and dust, and resistance to adhesion to a metal is
lowered.
[0043] The vinyl cyanide compound to be used in producing the
above-mentioned component (A-3) is the same as the vinyl cyanide
compound used in producing the above-mentioned component (A-1).
[0044] The aromatic vinyl compound to be used in producing the
above-mentioned component (A-3) is the same as the aromatic vinyl
compound used in producing the above-mentioned component (A-1).
[0045] The other copolymerizable vinyl compounds to be used in
producing the above-mentioned component (A-3) are the same as the
other copolymerizable vinyl compounds used in producing the
above-mentioned component (A-1).
[0046] Next, a production method of the styrene based resin
composition (A) will be described.
[0047] The mixing ratios of the components (A-1), (A-2) and (A-3)
in the styrene based resin compound (A) are 0.1 to 30%, preferably
0.5 to 20%, more preferably 1 to 15%, and even more preferably 1 to
7% for the component (A-1); 1 to 54.9%, preferably 1 to 44.5%, more
preferably 1 to 39%, and even more preferably 1 to 34% for the
component (A-2); and 45 to 95%, preferably 55 to 93%, more
preferably 60 to 88%, and even more preferably 65 to 86% for the
component (A-3).
[0048] If the ratio of the component (A-1) is less than 0.1%, the
effect of suppressing formation of the recesses becomes
insufficient and the surface property of the molded article is
lowered, and on the other hand, if it exceeds 30%, blow moldability
such as resistance to drawdown, secondary processability, and heat
resistance are lowered. Further, the ratio of the component (A-2)
is less than 1%, the impact resistance becomes insufficient, and on
the other hand, if it exceeds 54.9%, blow moldability, secondary
processability, and heat resistance are lowered. Furthermore, the
ratio of the component (A-3) is less than 45%, blow moldability and
secondary processability are lowered, and if it exceeds 95%, the
impact resistance becomes insufficient.
[0049] In addition, the component (A-3) may contain free copolymers
(copolymers which are not grafted to the rubber type polymers)
generated at the time of producing the component (A-1) and
component (A-2).
[0050] A content of the rubber type polymers in the entire
thermoplastic resin composition for blow molding of the present
invention is preferably 3 to 25%, more preferably 5 to 20%, and
even more preferably 10 to 20%. If the content of the rubber type
polymers is less than 3%, the impact resistance tends to be lowered
and on the other hand, if it exceeds 25%, the heat resistance of
the molded article tends to be lowered.
[0051] Further, the content of the .alpha.,.beta.-unsaturated
glycidyl ester compound in the entire thermoplastic resin
composition for blow molding of the present invention is preferably
0.001 to 5% from the viewpoints of the surface property of the
molded article and impact resistance.
[0052] The graft copolymers (A-1) and (A-2) can be produced by
graft polymerization of the above-mentioned monomer components by a
method of emulsion polymerization, suspension polymerization,
solution polymerization, bulk polymerization, or a combined method
thereof in the presence of the above-mentioned rubber type
copolymer. Among these, the emulsion polymerization is preferable.
In the above-mentioned graft polymerization, a polymerization
initiator, a chain transfer agent, an emulsifier (in the case of
the emulsion polymerization), or the like which have been commonly
used can be employed. The monomer mixture to be used for producing
the graft copolymers may be charged in entire amount at a time in
the presence of the rubber type polymer and polymerized or they may
be dividedly or continuously added little by little and
polymerized. Further, polymerization may be carried out by
combining these methods. Furthermore, the entire amount or a
portion of the rubber type polymer may be added during the
polymerization of the monomer mixture.
[0053] As the above-mentioned polymerization initiator, common
initiators are used corresponding to the polymerization method.
Examples of an initiator for emulsion polymerization may be redox
initiators combining organic peroxides such as cumene
hydroperoxide, diisopropylbenzene hydroperoxide, p-menthane
hydroperoxide or the like, with reducing agents such as
sugar-containing pyrophosphoric acid, sulfoxylate, or the like;
persulfates such as potassium persulfate; and peroxides such as
benzoyl peroxide (BPO), azobisisobutyronitrile, lauroyl peroxide,
tert-butyl peroxylaurate, tert-butyl peroxymonocarbonate, or the
like. The initiator may be an oil-soluble type or a water-soluble
type or those may be used in combination. The above-mentioned
initiators can be used alone or two or more of them can be used in
combination. The amount to be used of the above-mentioned
polymerization initiator is preferably 0.1 to 1.5% and more
preferably 0.2 to 0.7% based on the entire monomer components. In
addition, the polymerization initiator may be added at a time or
continuously to the polymerization system.
[0054] Further, examples of the chain transfer agent include
mercaptans such as octyl mercaptan, n-dodecyl mercaptan,
tert-dodecyl mercaptan, n-hexamethyl mercaptan, n-tetradecyl
mercaptan, tert-tetradecyl mercaptan, or the like; terpinolenes;
and .alpha.-methylstyrene dimmers. The above-mentioned chain
transfer agents may be used alone or two or more of them may be
used in combination. The amount to be used of the above-mentioned
chain transfer agent is preferably 0 to 5% based on the entire
monomers. In addition, the chain transfer agent may be added at a
time or continuously to the polymerization system.
[0055] Examples of the above-mentioned emulsifier include an
anionic surfactant and a nonionic surfactant. Examples of the
anionic surfactant may be sulfuric acid ester of a higher alcohol,
salts of alkylbenzenesulfonic acid such as dodecylbenzenesulfonic
acid; fatty acid sulfonic acid salts such as sodium lauryl sulfate;
higher fatty acid sulfonic acid salts and fatty acid phosphoric
acid salts. Further, examples of the nonionic surfactant include
alkyl ester type compounds of polyethylene glycol and alkyl ether
compounds of polyethylene glycol. The above-mentioned emulsifier
may be used alone or two or more of them may be used in
combination. The amount to be used of the above-mentioned
emulsifier is preferably 0.3 to 5% based on the entire
monomers.
[0056] The emulsion polymerization can be carried out in known
conditions in accordance with the types of vinyl based monomers and
polymerization initiators. Latexes obtained by the emulsion
polymerization are generally refined by coagulating them with a
coagulant, making the polymer components be a powder, and
thereafter washing the powder with water and drying the powder. As
the coagulant, inorganic salts such as calcium chloride, magnesium
sulfate, magnesium chloride, and sodium chloride; inorganic acid
such as sulfuric acid and hydrochloric acid; and organic acids such
as acetic acid and lactic acid may be employed.
[0057] In the case of producing a graft copolymer containing two or
more of the above-mentioned graft copolymers, resins may be
isolated from the respective latexes and mixed, however, as another
method, a mixture of latexes containing the respective resins can
be coagulated.
[0058] Conventionally known methods can be applied to a production
method of the above-mentioned graft polymers by solution
polymerization, bulk polymerization, and bulk-suspension
polymerization.
[0059] The graft ratio of the above-mentioned graft copolymers
(A-1) and (A-2) is generally 10 to 200%, preferably 30 to 120%, and
more preferably 40 to 80%. If the graft ratio is less than 10%, the
impact resistance of the molded article containing the
thermoplastic resin composition for blow molding of the present
invention tends to be lowered, and on the other hand, if the graft
ratio exceeds 200%, moldability tends to be lowered.
[0060] Herein, the graft ratio (% by weight) can be calculated
according to the following equation (1):
Graft ratio (% by weight)={(T-S)/S}.times.100 (1)
[0061] In the above-mentioned equation (1), T denotes a weight (g)
of an insoluble content obtained by charging 1 g of the
above-mentioned graft copolymer (A-1) or (A-2) into 20 ml of
acetone, shaking the mixture for 2 hours by a shaking apparatus,
successively carrying out centrifugal separation for 60 minutes by
a centrifuge separator (rotation speed: 23,000 rpm), and thus
separating the insoluble content and the soluble content. S denotes
the weight (g) of the rubber type polymer contained in 1 g of the
graft copolymer (A-1) or (A-2).
[0062] The above-mentioned graft ratio can be easily controlled by
adjusting the types and amounts of a polymerization initiator, a
chain transfer agent, an emulsifier, a solvent, or the like and
also a polymerization time, a polymerization temperature, or a
charging manner in the case of producing the above-mentioned graft
copolymers.
[0063] The above-mentioned copolymer (A-3) can be produced by
polymerizing a monomer mixture using a similar polymerization
initiator to those which are employed for producing the
above-mentioned graft copolymers (A-1) and (A-2). A polymerization
method is preferably solution polymerization, emulsion
polymerization, bulk polymerization, or suspension polymerization,
or may be a production method by combining them. The method for
producing the copolymer (A-3) may be a method using a
polymerization initiator or a thermal polymerization method using
no polymerization initiator or a method by combining them.
[0064] The limiting viscosity [.eta.] of the acetone-soluble
content of the above-mentioned copolymer (A-3) (measured at
30.degree. C. in methyl ethyl ketone) is preferably 0.1 to 1.5
dl/g, more preferably 0.1 to 1.0 dl/g, even more preferably 0.2 to
0.8 dl/g, and especially preferably 0.3 to 0.7 dl/g. If the
limiting viscosity [.eta.] is less than 0.1 dl/g, the resistance to
drawdown is insufficient at the time of blow molding and a parison
tends to be broken or dropped, and the thickness of the molded
article tends to become uneven and further, the impact resistance,
chemical resistance, and oil-proofness tend to be decreased. On the
other hand, if the limiting viscosity [.eta.] exceeds 1.5 dl/g, the
blow moldability tends to be lowered.
[0065] The limiting viscosity [.eta.] is measured by the following
method. At first, the acetone-soluble content (acetonitrile in the
case of an acrylic rubber) of the copolymer is dissolved in methyl
ethyl ketone and 5 samples with different concentrations are
produced. Next, the reduced viscosity is measured at 30.degree. C.
for each concentration using an Ubbelohde viscometer and from the
results, the limiting viscosity [.eta.] is calculated. The unit is
dl/g.
[0066] After production of the respective components (A-1), (A-2)
and (A-3) of the styrene based resin composition (A), blending,
coagulation, granulation (pelletization) and the like may be also
carried out by known methods. For example, the styrene based resin
composition (A) may be obtained by salting-out, coagulating,
dewatering, and drying a mixture of the respective latexes of the
above-mentioned graft copolymer (A-1), graft copolymer (A-2), and
copolymer (A-3) to obtain a powder, mixing the powder by a Henshel
mixer, and pelletizing the powder by melt extrusion by a uniaxial
or multi-axial extruder. Further, it may be obtained by coagulating
the above-mentioned mixture of the latexes containing the
respective resins of the above-mentioned graft copolymer (A-1),
graft copolymer (A-2), and copolymer (A-3).
[0067] The graft ratio of the styrene based resin composition (A)
is generally 10 to 200%, preferably 20 to 120%, and more preferably
30 to 80%. If the graft ratio is less than 10%, the impact
resistance of the molded article containing the thermoplastic resin
composition for blow molding of the present invention tends to be
lowered and on the other hand, if the graft ratio exceeds 200%, the
moldability tends to be lowered.
[0068] The limiting viscosity [.eta.] of the acetone-soluble
content of the above-mentioned styrene based resin composition (A)
(measured at 30.degree. C. in methyl ethyl ketone) is preferably
0.1 to 1.5 dl/g, more preferably 0.1 to 1.0 dl/g, even more
preferably 0.2 to 0.8 dl/g, and especially preferably 0.3 to 0.7
dl/g. If the limiting viscosity [.eta.] is less than 0.1 dl/g, the
resistance to drawdown is insufficient at the time of blow molding
and a parison tends to be broken or dropped, and the thickness of
the molded article tends to become uneven and further, the impact
resistance, chemical resistance, and oil-proofness tend to be
decreased. On the other hand, if the limiting viscosity [.eta.]
exceeds 1.5 dl/g, the blow moldability tends to be lowered.
Antistatic Agent B: (Hereinafter, Also Referred to as "Component
(B)")
[0069] In the present invention, the antistatic agent (B) with a
melting point of 170.degree. C. or lower is added in an amount of
0.1 to 10 parts, preferably 0.5 to 7 parts, and more preferably 2
to 4 parts based on 100 parts of the above-mentioned styrene based
resin composition (A).
[0070] If the amount of the antistatic agent (B) is less than 0.1
part, the effect of suppressing adhesion of polished powder of a
molded article generated in the sanding process before coating and
dust during storage until coating to the molded article surface
becomes insufficient and the resin composition becomes easy to
adhere to a metal. On the other hand, if the amount of the
antistatic agent (B) exceeds 10 parts, the resistance to drawdown,
heat resistance, and surface property are lowered.
[0071] Further, if the melting point of the antistatic agent (B)
exceeds 170.degree. C., it becomes difficult for the component
having the antistatic effect to bleed to the molded article
surface, and the effect of suppressing adhesion of polished powder
of a molded article generated in the sanding process before coating
and dust during storage until coating to the molded article surface
becomes insufficient.
[0072] The above-mentioned melting point means a melting point
measured by DSC (differential scanning calorimeter) or a softening
point in the case that no melting point clearly appears, and
substantial measurement methods for them are as follows.
"DSC"
[0073] Measurement apparatus: TA DSC 2910 model
[0074] Manufacturer: TA-Instruments
[0075] Measurement conditions: according to JIS K7121; [0076]
nitrogen gas flow rate: 50 ml/min.; [0077] heating rate: 20.degree.
C./min.
"Softening Point"
[0078] (1) A beaker containing an antistatic agent is set in an oil
bath or a sand bath.
[0079] (2) While the antistatic agent in the beaker is stirred with
a thermometer, the temperature is increased.
[0080] (3) The softening point is defined as a point at which the
granular antistatic agent begins melting (becoming viscous).
[0081] An antistatic agent (B) to be used in the present invention
is not particularly limited as far as it has a melting point at
170.degree. C. or lower; for example, low molecular weight type
antistatic agents and high molecular weight type antistatic agents
can be exemplified. These antistatic agents may be any of anionic
type antistatic agents, cationic type antistatic agents and
nonionic antistatic agents, and can be used alone or two or more
can be used in combination.
[0082] Examples of the low molecular weight type antistatic agents
include anionic type antistatic agents, cationic type antistatic
agents, nonionic antistatic agents, metal alkoxides and their
derivatives, complex compounds, organic boron compounds, coated
silica, and the like.
[0083] Examples of the anionic type antistatic agents include
sodium alkylsulfonate, sodium alkylbenzenesulfonate, alkyl
phosphate, and the like; examples of the cationic type antistatic
agents include phosphonium alkylsulfonate, phosphonium
alkylbenzenesulfonate, tetraalkylammonium salts,
trialkylbenzylammonium salts, quaternary ammonium salts, and the
like; examples of the nonionic type antistatic agents include
polyhydric alcohol derivatives, alkylethanolamines, alkylbetaines,
sulfobetaine derivatives and the like; examples of metal alkoxides
and their derivatives include alkoxysilanes, alkoxytitaniums,
alkoxyzirconiums, and the like.
[0084] The alkyl group is preferably a linear alkyl group having 4
to 20 carbon atoms.
[0085] Examples of the high molecular weight type antistatic agents
include polyalkylene oxide based polymers, acryl based copolymers,
polyether based copolymers, quaternary ammonium salt based
copolymers, betaine based copolymers, polyamide based elastomers,
polyester based elastomers, polyalkylbenzenesulfonic acid salts,
ionomer resins, and the like.
[0086] Examples of the polyalkylene oxide based polymers include
polyethylene oxide-epichlorohydrin copolymers; examples of the
acryl based copolymers include polyethylene glycol-(meth)acrylate
copolymers and methoxypolyethylene glycol-(meth)acrylate
copolymers; examples of polyether based compounds include polyether
amides, polyether ester amides, polyether amide imides, polyether
esters and the like; examples of the quaternary ammonium salt based
copolymers include quaternary ammonium salt group-containing
(meth)acrylate copolymers, quaternary ammonium salt
group-containing maleimide copolymers, quaternary ammonium salt
group-containing methacrylimide copolymers and the like; and
examples of the betaine based copolymers are carbobetaine graft
copolymers and the like.
[0087] Any antistatic agent can be favorably used as the antistatic
agent (B) used in the present invention as far as it has melting
point at 170.degree. C. or lower, and the melting point of the
antistatic agent (B) is preferably 40 to 170.degree. C., more
preferably 50 to 170.degree. C., even more preferably 60 to
170.degree. C., especially preferably 70 to 170.degree. C., and
most preferably 80 to 170.degree. C. If the melting point exceeds
170.degree. C., the effect of suppressing adhesion of polished
powder of a molded article generated in the sanding process before
coating and dust during storage until coating to the molded article
surface cannot be exhibited. To suppress adhesion of polished
powder and dust, it is preferable for a component which has the
antistatic effect to bleed most quickly to the blow molded article
surface after blow molding. However, since, as compared with
injection molding, blowing molding is carried out at a low resin
temperature and a low shear rate speed at the time of molding, it
is supposed that an antistatic agent with a higher melting point is
difficult to be evaporated and to bleed to the surface of the blow
molded article than an antistatic agent with a lower melting point.
Accordingly, it is preferable to use a low molecular weight type
antistatic agent with a low melting point. However, taking it into
consideration that if a large amount of the low molecular weight
type antistatic agent with a low melting point is added to the
thermoplastic resin composition for blow molding, the heat
resistance tends to be lowered, it is particularly preferable to
use a low molecular weight type antistatic agent with a melting
point of 80 to 170.degree. C.
[0088] Further, in the present invention, the thermoplastic resin
composition for blow molding comprising the styrene based resin
composition (A) and the antistatic agent (B) can further contain at
least one compound (C) selected from the group consisting of
hydroxides and carbonates of alkali metals, hydroxides, carbonates,
and oxides of alkaline earth metals, talc (D), and a polyolefin
based wax (E).
[0089] At Least One Compound (C) Selected from the Group Consisting
of Hydroxides and Carbonates of Alkali Metals, Hydroxides,
Carbonates, and Oxides of Alkaline Earth Metals: (Hereinafter, Also
Referred to as "Component (C)")
[0090] Examples of the hydroxides of alkali metals as the component
(C) used in the present invention include lithium hydroxide, sodium
hydroxide, potassium hydroxide, rubidium hydroxide, cesium
hydroxide and the like; and examples of carbonates of alkali metals
include lithium carbonate, sodium carbonate, potassium carbonate,
rubidium carbonate, cesium carbonate and the like.
[0091] Examples of the hydroxides of alkaline earth metals include
beryllium hydroxide, magnesium hydroxide, calcium hydroxide,
strontium hydroxide, barium hydroxide and the like; examples of the
carbonates of alkaline earth metals include beryllium carbonate,
magnesium carbonate, strontium carbonate, barium carbonate and the
like; and examples of the oxides of alkaline earth metals include
beryllium oxide, magnesium oxide, calcium oxide, strontium oxide,
barium oxide and the like.
[0092] These compounds may be used alone or two or more of them may
be used in combination and particularly, magnesium hydroxide,
calcium hydroxide, magnesium oxide, calcium oxide, sodium
carbonate, and magnesium carbonate are preferable from the
viewpoints of the effect, safety, and economy, and magnesium
hydroxide is particularly preferable.
[0093] The amount to be used of the component (C) is preferably
0.01 to 10 parts, more preferably 0.1 to 3 parts, and even more
preferably 0.1 to 1 part based on 100 parts of the styrene based
resin composition (A). If the amount of the component (C) is less
than 0.01 part, the effect of suppressing increase of the viscosity
of the resin when the resin is stagnated in a barrel of a molding
apparatus becomes insufficient and on the other hand, if it exceeds
10 parts, the impact strength of the molded article tends to be
lowered.
[0094] The average particle diameter (weight average particle
diameter) of the hydroxides and carbonates of alkali metals,
hydroxides, carbonates, and oxides of alkaline earth metals for the
component (C) is preferably 4 .mu.m or smaller. If the average
particle diameter exceeds 4 .mu.m, the impact strength tends to be
lowered. The hydroxides and carbonates of alkali metals,
hydroxides, carbonates, and oxides of alkaline earth metals may be
used after a surface treatment with stearic acid, a silane coupling
agent, or the like.
Talc (D): (Hereinafter, Also Referred to as "Component (D)")
[0095] The talc (D) to be used in the present invention is not
particularly limited, however it is preferred to use magnesium
silicate hydrate (4SiO.sub.2-3MgO--H.sub.2O) containing, as main
components, about 60% by weight of SiO.sub.2 and about 30% by
weight of MgO.sub.2.
[0096] The amount to be used of the component (D) is preferably
0.01 to 5 parts, more preferably 0.1 to 3 parts, and even more
preferably 0.3 to 1 part based on 100 parts of the styrene based
resin composition (A). If the amount of the component (D) is less
than 0.01 part, the effect of providing a resin with resistance to
adhesion to a metal becomes insufficient, and on the other hand, if
it exceeds 5 parts, the impact strength of the molded article tends
to be lowered.
[0097] The average particle diameter (weight average particle
diameter) of the talc (D) is preferably 5 .mu.m or smaller, and if
it exceeds 5 .mu.m, the impact strength tends to be lowered. Those
with different average particle diameters may be used in
combination for the talc (D). Further, talc may be used after a
surface treatment with a silane coupling agent or the like.
Polyolefin Based Wax (E): (Hereinafter, Also Referred to as
"Component (E)")
[0098] As the polyolefin based wax (E) used in the present
invention, polyethylene wax is preferable. The number average
molecular weight is not particularly limited, however it is
preferably 3000 or lower and more preferably 300 to 1500. If the
number average molecular weight exceeds 3000, the processability at
the time of blow molding tends to be lowered.
[0099] The polyolefin based wax (E) can be blended in an amount of
preferably 0.01 to 5 parts, more preferably 0.1 to 3 parts, and
even more preferably 0.3 to 1 part based on 100 parts of the
styrene based resin composition (A).
[0100] If the amount of the component (E) is less than 0.01 part,
the secondary processability such as sanding property (easiness for
sanding) is lowered, and on the other hand, if it exceeds 5 parts,
the heat resistance of the molded article tends to be lowered and
the surface appearance due to bleeding tends to be
deteriorated.
[0101] The thermoplastic resin composition for blow molding of the
present invention may further contain, if necessary, various kinds
of additives such as an antioxidant, a lubricant, an inorganic
filler, an organic filler, a metal filler, a fibrous filler,
graphite, carbon nanotubes, a thermal stabilizer, an ultraviolet
absorbent, a frame retardant, an anti-aging agent, a plasticizer,
an anti-bacterial agent, a coloring agent, a foaming agent, within
the range where the object of the present invention is not
damaged.
[0102] Among them, an antioxidant is preferably used for improving
thermal stability such as suppression of impact strength decrease
by heating hysteresis. Further, the lubricant is preferably used
for improving the moldability at the time of blow molding,
resistance to adhesion to a metal, surface property of the blow
molded article and impact strength, and lowering the winding
property of the resin at the time of drawdown.
Antioxidant (F): (Hereinafter, Also Referred to as Component
(F))
[0103] As the antioxidant (F), it is preferable to add one or more
of antioxidants selected from the group consisting of phenol based
antioxidants, phosphite based antioxidants, and thioether based
antioxidants. Further, combined use of the phenol based
antioxidants, phosphite based antioxidants, and thioether based
antioxidants causes a synergetic effect and thus even with a small
amount, a significant effect can be obtained.
[0104] The amount to be used of the component (F) is preferably 0.1
to 5 parts and more preferably 0.2 to 3 parts based on 100 parts of
the styrene based resin composition (A). If the amount of the
component (F) is less than 0.1 part, the addition effect tends to
exhibit insufficiently, and on the other hand, if it exceeds 5
parts, the above-mentioned addition effect tends to be saturated
and the heat resistance tends to be lowered.
Lubricant (G): (Hereinafter, Also Referred to as Component (G))
[0105] As the lubricant (G), it is possible to use one or more kind
lubricants selected from amide based lubricants such as fatty acid
amides, alkylene-bis-fatty acid amides and the like; hydrocarbon
based lubricants, fatty acid based lubricants, higher alcohol based
lubricants, ester based lubricants, metal soap and the like.
[0106] The amount to be used of the component (G) is preferably 0.1
to 5 parts and more preferably 0.2 to 3 parts based on 100 parts of
the styrene based resin composition (A). If the amount of the
component (G) is less than 0.1 part, the addition effect tends to
exhibit insufficiently and on the other hand, if it exceeds 5
parts, the above-mentioned addition effect tends to be saturated
and the heat resistance tends to be lowered.
[0107] Further, the thermoplastic resin composition for blow
molding of the present invention may contain, if necessary, other
resins such as polyethylene, polybutylene terephthalate,
polyethylene terephthalate, polycarbonate, polyamide and the like
within the range where the object of the present invention is not
damaged.
[0108] The thermoplastic resin composition for blow molding of the
present invention can be produced by mixing the respective
components at the prescribed mixing ratios by a tumbler mixer or a
Henshel mixer or the like, and melting and kneading under suitable
conditions using a mixing apparatus such as a uniaxial extruder, a
biaxial extruder, Bumbury's mixer, a kneader, a loader, a
feeder-loader and the like. Further, at the time of mixing and
kneading the respective components, the respective components may
be charged at a time and mixed or may be added and kneaded in
multi-steps or dividedly. After kneading using a Bumbury's mixer, a
kneader, or the like, the mixture may be pelletized by an extruder.
The melting and kneading temperature is generally 200 to
300.degree. C. and preferably 220 to 280.degree. C.
[0109] The thermoplastic resin composition for blow molding of the
present invention obtained in such a manner as aforesaid may be
molded into various kinds of molded articles by injection molding,
sheet-forming molding, vacuum molding, profile extrusion molding,
foam molding, injection compression molding, press molding, blow
molding or the like, and it is particularly preferably molded by
blow molding.
[0110] Examples of the above-mentioned blow molding, besides common
blow molding methods, include a sheet parison method, a cold
parison method, a bottle pack method, an injection blow method, a
stretching blow method and the like. Any method among them may be
employed, however, from the viewpoints of blow up property and
surface property, blow molding with a parison or a sheet heated to
200.degree. C. or higher is preferable. Further, in order to obtain
a better effect, at the time of expanding a parison or a sheet, an
inert gas such as nitrogen, carbon dioxide, helium, neon, argon, or
the like may be employed in place of air.
[0111] The thermoplastic resin composition for blow molding of the
present invention and its molded article can be used preferably for
automobiles and two-wheel vehicles, e.g. a bumper, an air spoiler,
a rear spoiler, a radiator grill, a scooter housing and the like.
They can be used preferably for housing use, e.g. a partition, a
top panel of a desk, furniture, a side cover in a bathtub, and the
like; and domestic electric appliances, e.g. a door of a
refrigerator, various kinds of housings, and office instruments,
and the like.
EXAMPLES
[0112] The present invention will be explained in more detail with
reference to Examples and Comparative Examples, however, the
present invention should not be limited to these Examples.
(1) Production of Thermoplastic Resin Composition for Blow
Molding
(1-1) Preparation of Styrene Based Resin (A)
Graft Copolymer (A-1)
[0113] A polymerization container equipped with a stirrer was
charged with 280 parts of water, 70 parts (in terms of a solid
content) of polybutadiene latex (average particle diameter: 0.18
.mu.m, gel content: 90%), 0.3 part of sodium formaldehyde
sulfoxylate, 0.0025 part of ferrous sulfate, and 0.01 part of
ethylenediaminetetraacetic acid disodium salt and after
deoxidation, the mixture was heated to 60.degree. C. with stirring
in nitrogen current, and successively, 30 parts of a monomer
mixture containing 3 parts (10% in the monomer mixture) of glycidyl
methacrylate, 6 parts (20% in the same) of acrylonitrile, and 21
parts (70% in the same) of styrene and 0.3 part of cumene
hydroperoxide was continuously added dropwise at 60.degree. C. over
5 hours. After completion of dropwise addition, the polymerization
temperature was increased to 65.degree. C. and after 1 hour
stirring was carried out, the polymerization was finished to obtain
a latex. The latex was salted out with calcium chloride and
washing, filtering and drying processes were carried out to obtain
a powdery graft copolymer (a-1). The polymerization conversion was
98% and the graft ratio was 37%. About 10% of the monomer mixture
was not grafted onto polybutadiene latex and monomers were
copolymerized in the monomer mixture and therefore, a graft
copolymer (a-1) was a mixture containing about 96% of a graft
copolymer (A-1) and about 4% of a copolymer (A-3).
Graft Copolymer (A-2)
[0114] A graft copolymer (a-2) was obtained in the same manner as
that for obtaining the graft copolymer (a-1), except that 70 parts
(in terms of the solid content) of polybutadiene latex (average
particle diameter: 0.26 .mu.m, gel content: 90%) was used as the
rubber type polymer and that the composition of 30 parts of the
monomer mixture was changed to a monomer mixture containing 7 parts
(23% in the monomer mixture) of acrylonitrile and 23 parts (77% in
the same) of styrene. The polymerization conversion was 98% and the
graft ratio was 36%. About 10% of the monomer mixture was not
grafted onto a polybutadiene latex and monomers were copolymerized
in the monomer mixture and therefore, the graft copolymer (a-2) was
a mixture containing about 96% of a graft copolymer (A-2) and about
4% of a copolymer (A-3).
Copolymer (A-3)
[0115] Copolymer (a-3-1)
[0116] A polymerization container equipped with a stirrer was
charged with 250 parts of water and 1.0 part of sodium palmitate
and after deoxidation, the mixture was heated to 70.degree. C. with
stirring in nitrogen current. Further, 0.4 part of sodium
formaldehyde sulfoxylate, 0.0025 part of ferrous sulfate, and 0.01
part of ethylenediaminetetraacetic acid disodium salt were charged,
then 100 parts of a monomer mixture containing 50 parts (50% in the
monomer mixture) of .alpha.-methylstyrene, 29 parts (29% in the
same) of acrylonitrile, and 21 parts (21% in the same) of styrene
and 0.1 part of tert-dodecylmercaptan were mixed and continuously
added dropwise at 70.degree. C. over 7 hours. After completion of
dropwise addition, the polymerization temperature was increased to
75.degree. C. and after 1 hour stirring was carried out, the
polymerization was finished to obtain a latex. The latex was salted
out with calcium chloride and washing, filtering and drying
processes were carried out to obtain a powdery graft copolymer
(a-3-1). The polymerization conversion was 98% and the limiting
viscosity [.eta.] (at 30.degree. C. in methyl ethyl ketone) was
0.67 dl/g.
Copolymer (a-3-2)
[0117] A copolymer (a-3-2) was obtained in the same manner as the
copolymer (a-3-1), except that the composition of the 100 parts of
the monomer mixture was changed to a monomer mixture containing 50
parts (50% in the monomer mixture) of .alpha.-methylstyrene, 29
parts (29% in the same) of acrylonitrile, and 21 parts (21% in the
same) of styrene and that the amount of tert-dodecylmercaptan was
changed to 0.42 part. The polymerization conversion was 98% and the
limiting viscosity [.eta.] (at 30.degree. C. in methyl ethyl
ketone) was 0.44 dl/g.
Copolymer (a-3-3)
[0118] A copolymer (a-3-3) was obtained in the same manner as the
copolymer (a-3-1), except that the composition of the 100 parts of
the monomer mixture was changed to a monomer mixture containing 70
parts (70% in the monomer mixture) of .alpha.-methylstyrene, 26
parts (26% in the same) of acrylonitrile, and 4 parts (4% in the
same) of styrene and that the amount of tert-dodecylmercaptan was
changed to 0.2 part. The polymerization conversion was 98% and the
limiting viscosity [.eta.] (at 30.degree. C. in methyl ethyl
ketone) was 0.51 dl/g.
Copolymer (a-3-4)
[0119] N-phenylmalemide-styrene-acrylonitrile terpolymer,
"PAS-1460" (trade name: manufactured by Nippon Shokubai Co., Ltd.)
was used. The contents of N-phenylmalemide, styrene, and
acrylonitrile were 40%, 51%, and 9%, respectively.
(1-2) Antistatic Agent (B)
[0120] (b-1) Aliphatic sulfonate, an anionic surfactant, "TB-160"
(trade name: manufactured by Matsumoto Yushi Seiyaku Co., Ltd.,
melting point 162.degree. C. (value in catalog (softening point)
115.degree. C.) was used. (b-2) A mixture of polyoxyethylene alkyl
(C8 to C18) amine, a cationic surfactant, and magnesium stearate
(melting point 49.degree. C. (value in catalog 55.degree. C.)) was
used. (b-3) Stearic acid monoglyceride (glycerin fatty acid ester),
a nonionic surfactant, "RIKEMAL S-100" (trade name: manufactured by
Riken Vitamin Co., Ltd., melting point 74.degree. C. (value in
catalog 66.degree. C.)) was used. (b-4) Aliphatic mono- and
di-glyceride boric acid ester, a high molecular weigh type
antistatic agent, "RESISTAT PE-139" (trade name: manufactured by
Dai-ichi Kogyo Seiyaku Co., Ltd., melting point 65.degree. C.
(value in catalog 59 to 65.degree. C.)) was used. (b-5) Anionic
surfactant-mixed polyether copolymerized ester "TEP-008" (trade
name: manufactured by Takemoto Oil and Fat Co., Ltd., melting point
198.degree. C. (value in catalog 180.degree. C.)) was used. (b-6)
Polyether ester amide block polymer "PELESTAT M-140" (trade name:
manufactured by Sanyo Chemical Industries, Ltd., melting point
192.degree. C. (value in catalog 198.degree. C.)) was used.
(1-3) Component (C)
[0121] (c-1): Magnesium hydroxide "KISUMA 5" (trade name:
manufactured by Kyowa Chemical Industry Co., Ltd., average particle
diameter 0.8 .mu.m) was used.
(1-4) Talc (D)
[0122] (d-1): Fine powder talc "MICRO ACE L-1" (trade name:
manufactured by Nippon Talc Co., Ltd., average particle diameter
1.8 .mu.m) was used.
(1-5) Polyolefin Based Wax (E)
[0123] (e-1): Polyethylene wax (low molecular weight polyethylene)
"Neowax ACL" (trade name: manufactured by Yasuhara Chemical Co.,
Ltd., number average molecular weight 700) was used.
(1-6) Antioxidant (F)
[0124] (f-1): Phenol based antioxidant "ADK STAB AO-50" (trade
name: manufactured by ADEKA Corporation) was used. (f-2): Phosphite
based antioxidant "ADK STAB PEP-36" (trade name: manufactured by
ADEKA Corporation) was used.
(1-7) Lubricant (G)
[0125] (g-1): Ethylene bisstearic acid amide "KAO WAX EB-G" (trade
name: manufactured by Kao Corporation) was used.
Example 1
[0126] As shown in Table 1, 1.0 part of the antioxidant (b-1), 0.5
part of the component (c-1), 0.5 part of talc (d-1), 0.5 part of
the polyolefin based wax (e-1), 0.5 part of the antioxidant (f-1),
0.3 part of the antioxidant (f-2), and 0.5 part of the lubricant
(g-1) were added to 100 parts of the styrene based resin
composition (A) containing 3.0 parts of the graft copolymer (a-1),
24.3 parts of the graft copolymer (a-2), 43.0 parts of the
copolymer (a-3-1), 9.0 parts of the copolymer (a-3-2), and 20.7
parts of the copolymer (a-3-3) (corresponding to 2.9 parts of the
graft copolymer (A-1), 23.3 parts of the graft copolymer (A-2), and
73.8 parts of the copolymer (A-3)) and the resultant mixture was
mixed by a Henshel mixer, and kneaded and pelletized at a set
temperature of 270.degree. C. using a vent type uniaxial extruder
(NVC-50, manufactured by Nakatani Kikai Co., Ltd) to obtain a resin
composition for blow molding.
Examples 2 to 19 and Comparative Examples 1 to 7
[0127] The resin compositions for blow molding of Examples 2 to 19
and Comparative Examples 1 to 7 were obtained in the same manner as
Example 1, except that the compositions were changed as shown in
Table 1 and Table 2.
TABLE-US-00001 TABLE 1 Examples 1 2 3 4 5 6 7 Blending [A] a-1 3.0
3.0 3.0 3.0 3.0 3.0 3.0 parts a-2 24.3 24.3 24.3 24.3 24.3 24.3
24.3 a-3-1 43.0 43.0 43.0 43.0 43.0 43.0 43.0 a-3-2 9.0 9.0 9.0 9.0
9.0 9.0 9.0 a-3-3 20.7 20.7 20.7 20.7 20.7 20.7 20.7 a-3-4 [B] b-1
1.0 2.0 3.0 4.0 5.0 10.0 b-2 1.0 b-3 b-4 b-5 b-6 [C] c-1 0.5 0.5
0.5 0.5 0.5 0.5 0.5 [D] d-1 0.5 0.5 0.5 0.5 0.5 0.5 0.5 [E] e-1 0.5
0.5 0.5 0.5 0.5 0.5 0.5 [F] f-1 0.5 0.5 0.5 0.5 0.5 0.5 0.5 f-2 0.3
0.3 0.3 0.3 0.3 0.3 0.3 [G] g-1 0.5 0.5 0.5 0.5 0.5 0.5 0.5
Composition Component A-1 % 2.9 2.9 2.9 2.9 2.9 2.9 2.9 Component
A-2 23.3 23.3 23.3 23.3 23.3 23.3 23.3 Component A-3 73.8 73.8 73.8
73.8 73.8 73.8 73.8 Contents of the below-mentioned components of
thermoplastic resin compositions for blow molding Rubber type
polymer 19.1 19.1 19.1 19.1 19.1 19.1 19.1
.alpha.,.beta.-unsaturated 0.09 0.09 0.09 0.09 0.09 0.09 0.09
glycidyl ester compound Evaluation Surface intrinsic .OMEGA.
1.0E+14 2.1E+12 1.6E+10 1.4E+10 1.3E+10 1.2E+10 3.5E+14 results
resistance Dust adhesion .DELTA. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .DELTA. Surface property
.largecircle. .largecircle. .largecircle. .largecircle.
.DELTA.~.largecircle. .DELTA. .largecircle. Resistance to
.largecircle. .largecircle.~.circleincircle. .circleincircle.
.circleincircle. .circleincircle. .circleincircle. .DELTA. adhesion
to metal Resistance to .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .DELTA.~.largecircle. .largecircle.
drawdown Deflection .degree. C. 95 94 94 93 92 91 93 temperature
under load Low temperature J 42 44 45 45 45 46 40 falling weight
impact strength Examples 8 9 10 11 12 13 14 Blending [A] a-1 3.0
3.0 3.0 3.0 3.0 3.0 3.0 parts a-2 24.3 24.3 24.3 24.3 24.3 24.3
24.3 a-3-1 43.0 43.0 43.0 43.0 43.0 43.0 43.0 a-3-2 9.0 9.0 9.0 9.0
9.0 9.0 9.0 a-3-3 20.7 20.7 20.7 20.7 20.7 20.7 20.7 a-3-4 [B] b-1
3.0 b-2 3.0 5.0 b-3 1.0 3.0 5.0 b-4 1.0 b-5 b-6 [C] c-1 0.5 0.5 0.5
0.5 0.5 0.5 [D] d-1 0.5 0.5 0.5 0.5 0.5 0.5 [E] e-1 0.5 0.5 0.5 0.5
0.5 0.5 [F] f-1 0.5 0.5 0.5 0.5 0.5 0.5 0.5 f-2 0.3 0.3 0.3 0.3 0.3
0.3 0.3 [G] g-1 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Composition Component
A-1 % 2.9 2.9 2.9 2.9 2.9 2.9 2.9 Component A-2 23.3 23.3 23.3 23.3
23.3 23.3 23.3 Component A-3 73.8 73.8 73.8 73.8 73.8 73.8 73.8
Contents of the below-mentioned components of thermoplastic resin
compositions for blow molding Rubber type polymer 19.1 19.1 19.1
19.1 19.1 19.1 19.1 .alpha.,.beta.-unsaturated 0.09 0.09 0.09 0.09
0.09 0.09 0.09 glycidyl ester compound Evaluation Surface intrinsic
.OMEGA. 2.8E+13 3.4E+12 7.8E+13 2.0E+10 1.2E+10 1.6E+14 3.1E+13
results resistance Dust adhesion .DELTA. .largecircle. .DELTA.
.largecircle. .largecircle. .DELTA. .DELTA. Surface property
.largecircle. .DELTA.~.largecircle. .largecircle. .largecircle.
.DELTA.~.largecircle. .largecircle. .DELTA. Resistance to
.largecircle.~.circleincircle. .largecircle.~.circleincircle.
.largecircle. .largecircle.~.circleincircle. .circleincircle.
.largecircle. X~.DELTA. adhesion to metal Resistance to
.largecircle. .largecircle. .largecircle. .largecircle. .DELTA.
.largecircle. .largecircle. drawdown Deflection .degree. C. 89 87
92 88 83 92 93 temperature under load Low temperature J 40 42 40 42
43 40 43 falling weight impact strength Examples 15 16 17 18 19
Blending [A] a-1 3.0 10.0 18.0 3.0 3.0 parts a-2 24.3 15.6 8.1 43.4
8.1 a-3-1 33.0 30.0 13.0 8.0 73.0 a-3-2 9.0 30.0 54.0 9.0 9.0 a-3-3
20.7 14.4 6.9 36.6 6.9 a-3-4 10.0 [B] b-1 3.0 3.0 3.0 3.0 3.0 b-2
b-3 b-4 b-5 b-6 [C] c-1 0.5 0.5 0.5 0.5 0.5 [D] d-1 0.5 0.5 0.5 0.5
0.5 [E] e-1 0.5 0.5 0.5 0.5 0.5 [F] f-1 0.5 0.5 0.5 0.5 0.5 f-2 0.3
0.3 0.3 0.3 0.3 [G] g-1 0.5 0.5 0.5 0.5 0.5 Composition Component
A-1 % 2.9 9.6 17.3 2.9 2.9 Component A-2 23.3 15.0 7.8 41.6 7.8
Component A-3 73.8 75.4 74.9 55.5 89.3 Contents of the
below-mentioned components of thermoplastic resin compositions for
blow molding Rubber type polymer 19.1 17.9 18.3 32.5 7.6
.alpha.,.beta.-unsaturated 0.09 0.30 0.54 0.09 0.09 glycidyl ester
compound Evaluation Surface intrinsic .OMEGA. 2.5E+10 2.1E+10
1.8E+10 3.1E+10 1.9E+10 results resistance Dust adhesion
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. Surface property .largecircle. .DELTA.~.largecircle.
.DELTA. .DELTA. .largecircle. Resistance to .circleincircle.
.largecircle. .largecircle. .largecircle. .largecircle. adhesion to
metal Resistance to .DELTA. .DELTA. .DELTA. .DELTA. .DELTA.
drawdown Deflection .degree. C. 98 94 93 86 98 temperature under
load Low temperature J 43 31 13 54 15 falling weight impact
strength Notes: The component A-3 is the total of a-3-1~4 and a
free AS contained in a-1 and a-2. In Table, "empty space (blank)"
indicates "0.0 (No presence)".
TABLE-US-00002 TABLE 2 Comparative Examples 1 2 3 4 5 6 7 Blending
[A] a-1 3.0 3.0 20.0 3.0 3.0 parts a-2 24.3 24.3 29.7 24.3 24.3
a-3-1 43.0 43.0 45.0 20.0 43.0 43.0 100.0 a-3-2 9.0 9.0 60.0 9.0
9.0 a-3-3 20.7 20.7 25.3 20.7 20.7 a-3-4 [B] b-1 15.0 3.0 3.0 3.0
b-2 b-3 b-4 b-5 5.0 b-6 5.0 [C] c-1 0.5 0.5 0.5 0.5 0.5 0.5 0.5 [D]
d-1 0.5 0.5 0.5 0.5 0.5 0.5 0.5 [E] e-1 0.5 0.5 0.5 0.5 0.5 0.5 0.5
[F] f-1 0.5 0.5 0.5 0.5 0.5 0.5 0.5 f-2 0.3 0.3 0.3 0.3 0.3 0.3 0.3
[G] g-1 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Compositions Component A-1 %
2.9 2.9 19.2 2.9 2.9 Component A-2 23.3 23.3 28.5 23.3 23.3
Component A-3 73.8 73.8 71.5 80.8 73.8 73.8 100.0 Contents of the
below-mentioned components of thermoplastic resin compositions for
blow molding Rubber type polymer 19.1 19.1 20.8 14.0 19.1 19.1
.alpha.,.beta.-unsaturated 0.09 0.09 0.50 0.09 0.09 glycidyl ester
compound Evaluation Surface intrinsic .OMEGA. >1E+16 -- 2.3E+13
3.6E+10 2.3E+15 3.0E+15 -- results resistance Dust adhesion X --
.DELTA. .largecircle. X X -- Surface property .largecircle. X X
.DELTA. .DELTA. .DELTA. Molding is Resistance to X .circleincircle.
.DELTA. .DELTA. .DELTA. .DELTA. impossible. adhesion to metal
Resistance to .largecircle. X .largecircle. X .DELTA. .DELTA.
drawdown Deflection .degree. C. 95 -- 94 93 94 95 temperature under
load Low temperature J 41 -- 42 13 42 41 falling weight impact
strength Notes: The component A-3 is the total of a-3-1~4 and a
free AS contained in a-1 and a-2. In Table, "empty space (blank)"
indicates "0.0 (No presence)". In Table, "--" indicates no presence
of measured values since the measurement was not conducted.
(2) Evaluation Method
[0128] The measurement methods of the respective evaluation items
for Examples and Comparative Examples will be described below.
(2-1) Surface Intrinsic Resistance
[0129] Each test piece was obtained by injection molding a disk
having a diameter of 100 mm, a thickness of 2 mm and a gate in the
center by an injection molding machine IS25EP (manufactured by
Toshiba Machine Co., Ltd.). The molding conditions were a resin
temperature of 250.degree. C. and a mold temperature of 60.degree.
C. After each disk type test piece obtained in the above-mentioned
method was left under conditions of a temperature at 23.degree. C.
and a humidity at 50% RH for 24 hours, the surface intrinsic
resistance (.OMEGA.) was measured by a resistance meter (trade
name: HIGH RESISTANCE METER (4339B: HIGH RESISTANCE METER+16008:
RESISTIVITY CELL), manufactured by Agilent Technologies Japan,
Ltd.) at applied voltage of 1000 V.
(2-2) Dust Adhesion
[0130] Using the resin compositions of Examples and Comparative
Examples, a common ABS resin having no antistatic effect, and a
static electricity-controlled ABS resin having antistatic effect,
disk type test pieces having a diameter of 100 mm and a thickness
of 2 mm, same as that used for the above-mentioned (2-1) surface
intrinsic resistance evaluation were set in a manner that the disk
faces of the test pieces were set vertically. After these test
pieces were left in a room until the test piece of the common ABS
resin was entirely covered with dust, the dust adhesion state to
the disk face of respective test pieces was evaluated by visual
observation by the following method.
[0131] On the basis of the dust adhesion states of the test pieces
of the common ABS resin having no antistatic effect and the static
electricity-controlled ABS resin having antistatic effect, the
evaluation was carried out by relatively comparing the dust
adhesion states of the test pieces of the resin compositions of
Examples and Comparative Examples. The evaluation criteria are
shown below.
.smallcircle.: Dust adhesion was almost the same as that of the
test piece of the static electricity-controlled ABS resin; .DELTA.:
Dust adhesion was about middle between that of the test piece of
the static electricity-controlled ABS resin and that of the test
piece of the common ABS resin; and x: Dust adhesion was almost the
same as that of the test piece of the common ABS resin.
[0132] Meanwhile, "ABS150" (manufactured by Techno Polymer Co.,
Ltd.) was used as the common ABS resin having no antistatic effect
and "EXCELLOY EK 10" (manufactured by Techno Polymer Co., Ltd.) was
used as the static electricity-controlled ABS resin, which is a
sustainable antistatic and conductive material.
[0133] The evaluation results prove that the polished powder at the
time of sanding and dust during storage hardly adheres as the
evaluation results are close to those of the static
electricity-controlled ABS resin, and thus these test pieces are
judged excellent in dust adhesion property.
(2-3) Surface Property
[0134] Cylindrical blow molded articles with a diameter of 70 mm, a
length of 400 mm, and a thickness of 3 mm were produced by blow
molding by a blow molding machine DA-50 (manufactured by PLACO Co.,
Ltd.). The molding conditions were parison temperature of
240.degree. C., injection speed (%) of 90, screw rotation speed of
30 rpm, blow pressure of 8 kg/cm.sup.2 G (air), cooling time of 90
seconds, and mold temperature of 60.degree. C.
[0135] Uneven recessed inferior parts (recesses with a size of 0.02
mm or larger) observed in the surface (excluding the top and bottom
circular parts) of each cylindrical blow molded article obtained by
the above-mentioned method were counted by visual observation and
same measurement was carried out each for 5 molded articles and the
average of the number of recesses was calculated. The evaluation
was carried out based on the following criteria.
.smallcircle.: The number of the average recesses was less than 10,
.DELTA.: The number of the average recesses was not less than 10
and less than 20, and x: The number of the average recesses was not
less than 20.
[0136] As the evaluation results, as the number of the average
recesses is small, the surface property is excellent.
(2-4) Resistance to Adhesion to Metal
[0137] After 50 g of each thermoplastic resin composition for blow
molding was charged into "Labo-Plasto-Mill 4C150-10 (manufactured
by Toyo Seiki Co., Ltd.) set at 240.degree. C. and rotation speed
of 30 rpm, it was kneaded for 10 minutes. Thereafter, the die block
was disassembled from the Labo-Plasto-Mill and after a lapse of 3
minutes from completion of the kneading, the resin adhering to the
metal surface in the die block inside was separated by a nipper.
Thereafter, the surface area of the portion where the metal surface
was exposed by separating the resin adhering to the die block
inside was evaluated by visual observation.
The evaluation was carried out based on the following criteria.
.circle-w/dot.: 90% or more of resin adhering to the metal surface
was peeled off; .smallcircle.: Not less than 50% and less than 90%
of resin adhering to the metal surface was peeled off; .DELTA.: Not
less than 10% and less than 50% of resin adhering to the metal
surface was peeled off; and x: Less than 10% of resin adhering to
the metal surface was peeled off.
[0138] As the evaluation results, as the ratio of the resin
adhering to the metal surface was peeled more, the resin was less
adhesive to the metal and thus excellent in the resistance to
adhesion to a metal. As the resistance to adhesion to a metal is
better, the adhesion of the resin to a metal is lower.
(2-5) Resistance to Drawdown
[0139] Using the blow molding machine DA-50, a parison was injected
to a length of about 500 mm (parison weight: about 500 g) at
240.degree. C. parison temperature and the time until the parison
dropped and fell from a die was measured and the resistance to
drawdown was evaluated according to the following criteria.
.smallcircle.: Time until the parison dropping after parison
injection exceeded 60 seconds; .DELTA.: Time until the parison
dropping after parison injection was 20 to 60 seconds; and x: Time
until the parison dropping after parison injection was less than 20
seconds.
[0140] As the evaluation results, as the time to keep the parison
from dropping is longer, the resistance to drawdown is more
excellent.
(2-6) Deflection Temperature Under Load
[0141] Each test piece with a width of 10 mm, a height of 4 mm, and
a length of 80 mm was produced by an injection molding machine
J100E (manufactured by The Japan Steel Works, Ltd.). The molding
conditions were 250.degree. C. of molding temperature and
60.degree. C. of mold temperature. The evaluation was carried out
by a Flat-wise method at a load of 1.82 MPa according to ISO75.
[0142] As the evaluation results, as the deflection temperature
under load is higher, the heat resistance is higher.
(2-7) Low Temperature Falling Weight Impact Strength
[0143] After the cylindrical blow molded articles used in the
evaluation of the above-mentioned (2-3) surface property were left
at -30.degree. C. in a prefabricated thermostat bath for 2 hours, a
Du-Pont falling weight impact strength at -30.degree. C. (weight of
the weight.times.half breakage height) (J) was measured. As shown
in FIGS. 1(a) and 1(b), each cylindrical blow molded article 1 was
set on the tool 3 for fixing a molded article made of a metal in a
manner that the parting line 2 was set horizontally and a weight
was dropped to the center part of the cylindrical molded
article.
[0144] As the evaluation results, as the falling weight impact
strength (J) is higher, the low temperature falling weight impact
is more excellent.
[0145] From the results of Examples 1 to 19 of Table 1 and
Comparative Examples 1 to 7 of Table 2, the following are made
clear.
[0146] Examples 1 to 19 containing 0.01 to 10 parts of the
antistatic agent (B) with a melting point of 170.degree. C. or
lower to the styrene based resin (A) were excellent in dust
adhesion property, surface property (appearance), resistance to
adhesion to a metal, resistance to drawdown (moldability),
deflection temperature under load (heat resistance), and low
temperature falling weight impact strength (impact resistance).
[0147] Comparative Example 1 containing no antistatic agent (B) had
high surface intrinsic resistance and was inferior in dust adhesion
property and resistance to adhesion to a metal, as compared with
Examples containing an antistatic agent (B).
[0148] Comparative Example 2 containing 15 parts of the antistatic
agent (B) which is outside of the scope of the present invention
was inferior in surface property and resistance to drawdown and was
impossible to give a good blow molded article.
[0149] Comparative Example 3 containing no graft copolymer (A-1:
a-1) was inferior in surface property, and Comparative Example 4
containing no graft copolymer (A-2: a-2) was inferior in resistance
to drawdown and low temperature falling weight impact strength.
[0150] Comparative Examples 5 and 6 containing the antistatic
agents (b-5) and (b-6) having a melting point exceeding 170.degree.
C. as the antistatic agent (B) had high surface intrinsic
resistances and were inferior in dust adhesion property.
[0151] Comparative Example 7 using neither the graft copolymer
(A-1: a-1) nor the graft copolymer (A-2: a-2) was inferior in blow
moldability and was impossible to give a good blow molded
article.
[0152] In comparison of Examples 1 to 13 and Examples 15 to 19 with
the same compositions although the types and amounts of the
antistatic agents were different, it was found that Examples 1 to 6
using the antistatic agent (b-1) with a melting point in a range of
80 to 170.degree. C., the most preferable range, were excellent in
the balance among the dust adhesion property, surface property,
resistance to adhesion to a metal, resistance to drawdown,
deflection temperature under load, and low temperature falling
weight impact strength.
[0153] From results of Examples 1 to 6 containing antistatic agent
(b-1) in changed amounts, it was found that Examples 2 to 4
containing the antistatic agent (b-1) in an amount within a more
preferable range of 2 to 4 parts were excellent in the balance
among the dust adhesion property, surface property, resistance to
adhesion to a metal, resistance to drawdown, deflection temperature
under load, and low temperature falling weight impact strength.
[0154] From results of Example 3 and Examples 16 to 19 in which the
mixing ratios of the graft copolymer (A-1: a-1), the graft
copolymer (A-2: a-2), and the copolymer (A-3: a-34 to a-3-4) were
changed, it was found that Example 3 was excellent in the balance
among the dust adhesion property, surface property, resistance to
adhesion to a metal, resistance to drawdown, deflection temperature
under load, and low temperature falling weight impact strength.
[0155] Examples 1 to 13 and Examples 15 to 19 containing components
(C), (D) and (E) were more excellent in the balance among the dust
adhesion property, surface property, and resistance to adhesion to
a metal than Example 14 which did not contain them.
[0156] Further, Example 15 containing the copolymer (a-3-4)
obtained by copolymerizing N-phenylmaleimide as the other
copolymerizable components was excellent in deflection temperature
under load.
INDUSTRIAL APPLICABILITY
[0157] The thermoplastic resin composition for blow molding of the
present invention is not only excellent in surface property of a
blow molded article, impact resistance, heat resistance, and blow
moldability such as resistance to drawdown, but also gives a molded
article having the molded article surface to which polished powder
generated in a sanding process before coating hardly adheres and
also the molded article surface to which dust hardly adheres during
storage until the coating process. Accordingly, the work for
removing them before coating is lessened and productivity of the
blow molded article can remarkably improved.
[0158] Further, addition of at least one compound (C) selected from
the group consisting of hydroxides and carbonates of alkali metals,
hydroxides, carbonates and oxides of alkaline earth metals, talc
(D), and a polyolefin based wax (E) to the above-mentioned resin
composition lowers the adhesion of the resin composition to a metal
and the resin composition adhering to a die at the time of blow
molding scarcely causes thermal deterioration and decomposition,
and therefore, there is less possibility of damaging the surface
appearance of the blow molded article. Further, since the resin
composition hardly adheres to the metal surfaces of the screw
surface and the barrel inner wall of a blow molding machine, the
workability of replacing the resin becomes excellent and the
productivity can be remarkably improved.
[0159] Moreover, fine irregularities are formed on the parison
surface at the time of blow molding, gas purging between the
parison surface and the mold surface occurs well, and furthermore,
since formation of recesses larger than the fine irregularities can
be suppressed, the work needed for the secondary processability
such as sanding to obtain a smooth coating face can be made easy.
Consequently, the present invention provides the remarkably
advantageous thermoplastic resin composition for blow molding for
obtaining a blow molded article such as an air spoiler or the like
which is required to have good surface appearance, and the blow
molded article obtained by molding the composition.
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